1. Technical Field
The invention relates to a photonic component having a substrate support with an optical waveguide thereon and an electrical conduction path.
2. Discussion of Related Art
A photonic component of this type is known from a publication by S. Mino et al. entitled "Loss reduction in a Coplanar waveguide on a Planar Light Waveguide Circuit (PLC) Platform by Quenching". A silicon substrate carries an optical waveguide, a laser diode, control electronics for the laser diode and electrical conduction paths forming coplanar electrical waveguides. Since the electrical conductivity of the silicon substrate increases with increasing frequency, the electrical conduction paths are not applied directly to the surface of the silicon substrate. Instead, the electrical conduction paths are separated from the silicon substrate by a thin insulating layer, which for the photonic component described in the publication consists of silica glass. Also used in the art are insulating layers made from polyimides or from other organic materials.
The insulating layers to be applied are usually very thin. It is in general not possible to apply thicker insulating layers, since optoelectronic components secured to the insulating layer would then be located too high above the inputs of the optical waveguides. Moreover, when the insulating layers become thicker, electrical conduction paths disposed thereon would have to be connected to lower lying components with bond wires. The tools for establishing an electrical connection through bond wires require substantial space. Such space is generally not available when photonic components are highly integrated, particularly proximate of laser bars.
When the insulating layers are very thin, the resulting electrical insulation is insufficient. As also mentioned in the aforementioned publication, the electrical losses at high frequencies are substantial even if the electrical conduction paths are placed on top of an insulating layer.